MadSci Network: Medicine

Re: If a man falls in a river that is frozen, would they drown first or freeze

Date: Mon Dec 6 18:06:49 1999
Posted By: Layne Johnson, Undergraduate
Area of science: Medicine
ID: 942347144.Me

Hey, Joe!

I'm a physics fan, and usually answer questions about astronomy and 
physics.  But I'm also a volunteer fire fighter with EMT training, and 
that's why I feel I can answer your question.

The information I'm presenting here comes from "Emergency Care Seventh 
Edition", published by Brady in 1995.  It is the standard textbook for 

You probably know what wind chill is.  Water chill is like wind chill, but 
much more potent.  The human body looses 25 times more heat by being 
exposed to cold water than cold air.  It's even worse if the water is 
flowing around a person than if it's still, so being immersed in a 30 
degree river will cool you down faster than immersion in a 30 degree lake.

Surprisingly, the human body can't survive if the core temperature, or the 
temperature of the internal organs, falls below 80 degrees F.  We can walk 
around outside in temperatures below freezing and be just fine, for short 
periods of time.  Our extremities can get very cold, and we aren't in much 
danger.  But if we get cold inside, our heartbeat becomes erratic, we lose 
consciousness, and die.

Luckily for us, moving around and doing things generates heat inside our 
bodies.  If a man falls into a frozen river, he will try to get out, and 
the exercize he gets will help keep his core warm.

There are too many factors to let us say how long a man can survive in the 
cold of a frozen river.  Some of the variables are the speed the river is 
flowing, the size of the man, how warm he was before he fell in, how much 
body fat he has, and what his general health is like.

Still, let's hazard a guess, and say that the average sized, healthy man 
could snorkle in a frozen river for 20 minutes before losing 
consciousness, and 30 minutes before death occurs.

Let's compare that to drowning.  Only 10% of drowning victims die from lack 
of air.  The other 90% panic and inhale water, which kills faster than 
holding their breath does.  Even in the lungs are dry and full of air, 
people die after 4-10 minutes of not breathing.

So lack of air would kill a man faster than the freezing water.

I hope this answers your question.

Layne Johnson

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